Inappropriate activation of a single enzyme, telomerase, is associated with the uncontrolled proliferation of cells seen in as many as 90 percent of all human cancers. Since the mid-1990s, when telomerase was first identified in human tumors, scientists have eyed the enzyme as an ideal target for developing broadly effective anti-cancer drugs. The important role of telomerase in cancer makes this enzyme an important drug target. I propose a structural biology approach to examine the function of telomerase and its role in human disease. Structural data can prove invaluable in explaining, as well as designing, biochemical and biophysical experiments. It can also be a very powerful tool for drug discovery. The long-term goal of my research plan is to use structural biology, in conjunction with biochemistry to understand how telomerase replicates telomere ends, and to apply this information to the pursuit of anti-cancer therapies.